Does anyone know what this aroma is or is called please ? It's difficult to describe but reminds me of sweets I ate in childhood and is very relaxing. Also is this aroma found in other species please ?

No, species that use pheromones to attract mates, identity their gender or their family so as to avoid inbreeding (as gulls do) have a highly developed sense of smell and parrots don't. It would not make any sense for nature to give them a way of attracting mates that can only be used when the animal is next to the other...

I have never been able to find any scientific source that would explain where, exactly, amazons' smell comes from or what it's for but the consensus is that they smell sweet (some people call it 'fruity') when they are clean and well-fed (lots of fruits and veggies) and musky when they are dirty and/or badly fed (as in high protein food mostly).

All parrots have a smell to them, just like any other animal on earth does, some stronger than others. Amazons, quakers and macaws smell stronger than other species but they all do...